This invention relates generally to ultrasound imaging systems, and more particularly the invention relates to an intracavity probe for trans-vaginal imaging and including an integrated biopsy adapter.
Ultrasound imaging has become an important tool in obstetrics for monitoring the fetus during early months of pregnancy and for guiding needles for the extraction of ovum from the ovary for in vitro fertilization and for chorionic villus sampling. Originally, the procedure included abdominal imaging and puncture. However, this procedure can be painful and risks puncturing the bowel loop. Further, large distance of the ovary, uterus, and the fetus to the probe in trans-abdominal scans limits image resolution. More recently, trans-vaginal imaging using an intracavitary probe has been developed and offers many advantages over trans-abdominal imaging. Importantly, the proximity of the organs to the probe during early pregnancy are only one to five centimeters from the vagina as compared to five to fifteen centimeters for trans-abdominal scans. Since the resolution of an image is approximately proportional to distance, the trans-vaginal image will be of superior resolution. Additionally, since less intervening tissue is between the probe and target the signal-to-noise ratio is greatly improved, especially in obese patients. Due to the short propagation distance, high frequency imaging and accurate tissue characterization using high frequency (e.g. 7-10 MHz) imaging is possible in trans-vaginal scans. Further, in trans-abdominal scanning a full bladder is required to serve as a "window" for imaging. This causes discomfort to the patient and may sometimes delay or compromise a scan due to a non-full bladder. Finally, ultrasonic needle guidance may be accomplished trans-vaginally for the extraction of ovum from the ovary and precise biopsy operations can be performed more safely and less painfully.
One intracavity probe now commercially available employs a mechanical section scanning element mounted inside an elongated housing for rotation therein. The scanning head is relatively large and the image quality is marginal. The probe does accommodate a biopsy needle. Another known probe includes an oscillating transducer in an elongated housing. To alter the image scan direction the elongated housing must be axially tilted in the vaginal cavity, causing discomfort and pain to the patient. The probe does not function as a biopsy needle guide.